anti-HCV Enzyme-linked Immunosorbent Assay Research Articles

Prevalence of Hepatitis C Virus Among Pregnant Women at Tertiary Care Hospital

Backgrounds: The prevalence study of HCV infection among pregnant women is limited in central India. Vertical transmission (Mother-to-child) has become the major cause of pediatric hepatitis C virus (HCV) infection. Thus, the present study aimed to evaluate the prevalence of hepatitis C among pregnant females attending antenatal clinics. Material and Methods: The cross-sectional study done at Malwanchal University, Indore Madhya Pradesh, from March 2019 to September 2022. The confirm diagnosis of HCV infection made by anti-HCV Enzyme-linked immunosorbent assay (ELISA) among enrolled pregnant women. Results: Out of 3254 pregnant women tested, 26 were found positive for HCV infection. The prevalence of 0.79% was observed. The majority of infection were found in age groups 21-25 years 11/26 (42.3%) and in 26-30 years 09/26 (34.6%). The study also concluded to the most positive pregnant women belonged to low-income groups and rural areas. Conclusion: Screening of pregnant women during each pregnancy, and testing infants born to mothers with HCV infection highly recommend to for the timely prevention of its transmission to infants. Keywords: Vertical transmission, pregnant women, HCV infection

Current status of hepatitis C virus among people living with human immunodeficiency virus in Egypt.

Human immunodeficiency virus (HIV)-hepatitis C virus (HCV) co-infection is increasing due to their similar routes of transmission. Co-infection poses a big challenge. Information on the prevalence of HCV infection in Egyptian HIV individuals is scarce. A cross-sectional study was conducted on 1004 HIV individuals who were recruited from July 2018 to March 2019. Blood samples obtained from HIV individuals were subsequently screened for HCV antibodies using the Murex anti-HCV (version 4) enzyme-linked immunosorbent assay test. HCV RNA was performed only on anti-HCV antibody-positive samples. Logistic regression was used to identify factors associated with HCV seroprevalence using SPSS (IBM, Armonk, NY, USA). Among 1004 participants, 349 exhibited a positive result for anti-HCV antibodies (34.8% [95% confidence interval 31.81 to 37.8]). The most commonly self-reported risk factor of HIV infection by the co-infected participants was intravenous drug use (IDU) (303/349 [86.8%]). In multinomial analysis, risk factors identified as statistically associated with HCV seroprevalence include IDU, history of surgical operations and dental procedures and HIV viral load (p<0.001, 0.032, <0.001 and 0.006, respectively). Under combination antiretroviral therapy (cART), the proportion of HIV mono-infected individuals with an undetectable HIV viral load was significantly higher than those with co-infection (p<0.0007). We also found that HIV-HCV co-infected participants exhibited significantly higher CD4+ cell counts than those with HIV mono-infection (p=0.04). The prevalence of HIV-HCV co-infection is higher in Egypt compared with other countries in Africa. It is essential to screen all HIV-infected patients for HCV infection for early identification, counselling and initiation of anti-HCV treatment.

Implementation of internal quality control program for monitoring of enzyme-linked immunosorbent assay performance at a blood center

BACKGROUND:Internal quality control (IQC) samples may be incorporated in enzyme-linked immunosorbent assay (ELISA) routinely for detection of errors occurring due to change in environmental conditions, test system, or operator performance. We have described methodology for preparation of IQC samples, monitoring of results using Levey–Jennings (LJ) charts and their interpretation. We have also described our experience of quality control in ELISA using IQC samples, identification of errors and corrections applied.MATERIALS AND METHODS:IQC samples for anti-HIV, hepatitis B surface antigen (HBsAg), and anti-HCV ELISA were prepared “in-house” using standard methodology. After validation of run, E-ratio of IQC sample was calculated and plotted on LJ chart. Further interpretation was done to detect the errors. LJ charts illustrating the performance of IQC samples on 180 runs for each ELISA were drawn and analyzed.RESULTS:For anti-HIV ELISA, violation of warning rule was found in 2 runs (1.11%). Only one run (0.55%) was rejected due to violation of rejection rule. For HBsAg ELISA, violation of warning rule was indicated in two runs (1.11%). Two runs (1.11%) were rejected due to violation of rejection rules. For anti-HCV ELISA, violation of warning rule was indicated in two runs (1.11%), whereas two runs were rejected due to violation of rejection rules. Comprehensive checks were performed for the evaluation of equipment calibration, handling, and storage temperature of reagents and operator's technique. A thorough investigation was undertaken according to the type of error.CONCLUSION:Inclusion of IQC with each ELISA run is valuable to check the assay performance, ensuring reliability and reproducibility of test results.

Detection of Anti-Hepatitis C virus and Hepatitis C virus RNA in Dried Blood Spot Specimens using Whatman no. 1 Filter Paper

Purpose: Dried blood spot (DBS) specimen simplifies blood collection, processing, storage and shipment and may reduce the cost of testing for hepatitis C virus (HCV) infection. We wanted to see if DBS using a cheap filter paper is reliable alternative to serum for detection of anti-HCV and HCV RNA. Materials and Methods: At a tertiary care hospital in Northeast India, we collected 91 paired DBS and serum specimens from patients at risk of HCV infection from July 2014 to June 2015. DBS was collected on Whatman No. 1 filter paper. After processing, the specimens were subjected to anti-HCV detection by a third-generation Enzyme-Linked Immunosorbent Assay (ELISA). The reactive DBS and serum specimens were further subjected to HCV RNA detection by polymerase chain reaction. The results were analysed in paired screen-positive study design. Results: Anti-HCV was detected in 9 (9.9%) DBS specimens and 10 (10.9%) serum specimens. There was statistically significant (P < 0.0001) correlation between the optical density values of DBS and serum specimens (Pearson r = 0.9181, 95% confidence interval: 0.8781–0.9453). HCV RNA was detected in 5/9 (55.6%) reactive DBS and 9/10 (90.0%) reactive serum specimens. There was no correlation between HCV RNA levels in the DBS and the serum specimens. The relative sensitivity rate and the relative false-positive rate of DBS anti-HCV ELISA were 0.89 and 1.00, respectively. Conclusions: DBS using Whatman No. 1 filter paper is quite reliable as serum for detection of anti-HCV. It can be useful in effective surveillance. However, it is not suitable for confirmation of chronic HCV infection.

Patients with dry eye without hepatitis C virus infection possess the viral RNA in their tears.

Dry eye is one of the suggested extrahepatic complications associated with hepatitis C virus (HCV) infection. HCV RNA has been detected from the tear fluid of patients with chronic HCV. There has been no literature evidence on the presence of HCV RNA in the tear fluid of patients with dry eye without HCV infection. In this study, tear fluid of patients with dry eye with no HCV infection was screened for the presence of HCV RNA. Tear fluid was collected from patients with dry eye (n = 36) and healthy controls (n = 20). Real-time polymerase chain reaction was performed to detect HCV RNA in the tear fluid. Anti-HCV enzyme-linked immunosorbent assay, alkaline phosphatase, and alanine aminotransferase tests were performed in the serum samples collected from 15 patients with dry eye. Viral RNA was detected in 58.3% of the patients. Serum samples collected from 15 patients with dry eye were negative for anti-HCV. Alkaline phosphatase levels were elevated in 12 of 15 patients. Alanine aminotransferase levels were normal in all 15 patients. The odds ratio for the presence of HCV RNA in patients with dry eye was 22.4. These results indicate a direct correlation between dry eye and HCV in non-HCV patients.

Novel Evolved Immunoglobulin (Ig)-Binding Molecules Enhance the Detection of IgM against Hepatitis C Virus

Detection of specific antibodies against hepatitis C virus (HCV) is the most widely available test for viral diagnosis and monitoring of HCV infections. However, narrowing the serologic window of anti-HCV detection by enhancing anti-HCV IgM detection has remained to be a problem. Herein, we used LD5, a novel evolved immunoglobulin-binding molecule (NEIBM) with a high affinity for IgM, to develop a new anti-HCV enzyme-linked immunosorbent assay (ELISA) using horseradish peroxidase-labeled LD5 (HRP-LD5) as the conjugated enzyme complex. The HRP-LD5 assay showed detection efficacy that is comparable with two kinds of domestic diagnostic kits and the Abbott 3.0 kit when tested against the national reference panel. Moreover, the HRP-LD5 assay showed a higher detection rate (55.9%, 95% confidence intervals (95% CI) 0.489, 0.629) than that of a domestic diagnostic ELISA kit (Chang Zheng) (53.3%, 95% CI 0.463, 0.603) in 195 hemodialysis patient serum samples. Five serum samples that were positive using the HRP-LD5 assay and negative with the conventional anti-HCV diagnostic ELISA kits were all positive for HCV RNA, and 4 of them had detectable antibodies when tested with the established anti-HCV IgM assay. An IgM confirmation study revealed the IgM reaction nature of these five serum samples. These results demonstrate that HRP-LD5 improved anti-HCV detection by enhancing the detection of anti-HCV IgM, which may have potential value for the early diagnosis and screening of hepatitis C and other infectious diseases.

Serial follow-up of repeat voluntary blood donors reactive for anti-HCV ELISA.

Background:Voluntary non-remunerated repeat blood donors are perceived to be safer than the first time blood donors. This study was planned for follow-up of previous hepatitis C virus (HCV) test results of anti-HCV enzyme-linked immunosorbent assay (ELISA) reactive repeat blood donors. The aim was to suggest a protocol for re-entry of the blood donors who are confirmed HCV negative by nucleic acid test (NAT) and recombinant immunoblot assay (RIBA). A group of repeat voluntary donors were followed retrospectively who became reactive on a cross sectional study and showed HCV reactivity while donating blood regularly.Material and Methods:A total of 51,023 voluntary non remunerated blood donors were screened for anti-HCV ELISA routinely. If anybody showed positivity, they were tested by two ELISA kits (screening and confirmatory) and then confirmed infection status by NAT and or RIBA. The previous HCV test results of repeat donors reactive by anti-HCV ELISA were looked back from the records. Data of donors who were repeat reactive with single ELISA kit (in the present study) were analyzed separately from those reactive with two ELISA kits (in the present study).Results:In this study, 140 (0.27%) donors who were reactive by anti HCV ELISA were included. Out of them, 35 were repeat voluntary donors and 16 (11.43%) were reactive with single ELISA kit. All 16 donors were reactive by single ELISA kit occasionally in previous donations. Their present ELISA positive donations were negative for HCV NAT and RIBA. A total of 19 (13.57%) donors were reactive with two ELISA kits. In their previous donations, the donors who were reactive even once with two ELISA kits were consistently reactive by the same two ELISA kits in their next donations also.Conclusion:Donor sample reactive by only single ELISA kit may not be considered as infectious for disposal as they were negative by NAT and or RIBA. One time ELISA positivity was found probably due to ELISA kit specificity and sensitivity. Donors reactive with two ELISA kit should be discarded as there is a high positivity with NAT/ RIBA. However, donors reactive by two ELISA kits and negative by NAT and RIBA should be followed up and may not be deferred permanently.

EVALUATION OF COMMERCIALLY AVAILABLE THIRD-GENERATION ANTI-HEPATITIS C VIRUS ENZYME-LINKED IMMUNOSORBENT ASSAY IN PATIENTS ON HAEMODIALYSIS

Restricted antibody reactivity to hepatitis C virus (HCV) synthetic peptides has been observed in HCV-infected patients on haemodialysis (HD). The aim of this study was to evaluate third-generation anti-HCV enzyme-linked immunosorbent assay (ELISA) test systems containing either synthetic peptide HCV antigens or recombinant HCV antigens or a combination of synthetic and recombinant antigens in screening of 69 chronic renal failure patients on HD for HCV infection. Seven patients were detected to have antibodies to HCV by the ‘recombinant HCV antigens’-containing kits, of which the recombinant immunoblot assay for HCV confirmed four cases. The recombinant kits had a sensitivity of 100% and a specificity of 66%. However, the ELISA kits with only synthetic HCV antigens failed to detect antibodies in any of the cases (zero sensitivity). Hence a recombinant protein containing ELISA test system is ideal for screening of HCV infection in patients on hemodialysis.

Evaluation of commercially available third-generation anti-hepatitis C virus enzyme-linked immunosorbent assay in patients on haemodialysis

Restricted antibody reactivity to hepatitis C virus (HCV) synthetic peptides has been observed in HCV-infected patients on haemodialysis (HD). The aim of this study was to evaluate third-generation anti-HCV enzyme-linked immunosorbent assay (ELISA) test systems containing either synthetic peptide HCV antigens or recombinant HCV antigens or a combination of synthetic and recombinant antigens in screening of 69 chronic renal failure patients on HD for HCV infection. Seven patients were detected to have antibodies to HCV by the 'recombinant HCV antigens'-containing kits, of which the recombinant immunoblot assay for HCV confirmed four cases. The recombinant kits had a sensitivity of 100% and a specificity of 66%. However, the ELISA kits with only synthetic HCV antigens failed to detect antibodies in any of the cases (zero sensitivity). Hence a recombinant protein containing ELISA test system is ideal for screening of HCV infection in patients on hemodialysis.

Risk factors for hepatitis C virus infection in male adults in Rawalpindi-Islamabad, Pakistan.

To identify risk factors associated with HCV infection in Islamabad-Rawalpindi. Fifty-seven cases and 180 controls were enrolled from various departments of the nine major hospitals of the Rawalpindi-Islamabad during July-September 1998. Cases were enzyme-linked immunosorbent assay (ELISA) positive for antibodies to HCV (anti-HCV), aged 20-70 years, and residents of Islamabad or Rawalpindi division. Controls were anti-HCV ELISA negatives of the same age range and from the same area. A structured questionnaire was used to collect data on demographic variables and potential risk factors, which was analysed by logistic regression to calculate crude and adjusted odds ratios (OR) and corresponding 95% confidence intervals (CI) for risk factors. The final multivariate logistic regression model revealed that after adjusting for age, cases were more likely to have received therapeutic injections in the past 10 years (1-10 vs. 0 therapeutic injections; adjusted OR=2.8, 95% CI: 1.1-7.1; > 10 vs. 0 therapeutic injections; adjusted OR=3.1, 95% CI: 1.2-7.9) and were significantly more likely to have daily face (adjusted OR=5.1, 95% CI: 1.5-17.0) and armpit shaves (adjusted OR=2.9, 95% CI: 1.3-6.5) by a barber. HCV control and prevention programs in this region should include safe injection practices and educate men about the risk of HCV infection from contaminated instruments used by barbers.

Detection of de novo Hepatitis C Virus Infection by Polymerase Chain Reaction in Hemodialysis Patients

Patients on chronic hemodialysis (HD) treatment have been identified by serological testing, including second- and third-generation enzyme-linked immunosorbent assay (ELISA), as a high-risk group for hepatitis C virus (HCV) infection. Previous studies have shown that de novo cases of HCV may occur in HD units in the absence of other parenteral exposures, which suggests the spread of HCV between patients. In addition, the reverse-transcription polymerase chain reaction (RT-PCR), which directly detects HCV virus, has identified HCV infection in chronic HD patients who are seronegative. The aim of this study was to determine the incidence of HCV infection detected by RT-PCR technology in a large cohort of chronic HD patients. One hundred and twenty chronic HD patients, HCV-negative by serological assays (second-generation ELISA) and molecular techniques (branched DNA and RT-PCR), were observed for a mean period of 9.5 months. They were tested monthly for serum alanine aminotransferase levels (ALT) and by second-generation ELISA. At the end of the follow-up period, they were again evaluated by branched DNA and RT-PCR testing. HCV RNA was detected in patients’ sera by RT followed by PCR using two separate primer sets from the 5′-untranslated region of the HCV genome. Southern blot was performed using a digoxigenin-labeled probe. Two patients who had HCV RNA detectable by RT-PCR at the end of the follow-up period remained branched-DNA-negative. Thus, the incidence of de novo acquisition of HCV infection in the current investigation was 2.1% per year. In 1 patient RT-PCR positivity and anti-HCV ELISA seroconversion occurred. The 2nd patient remained anti-HCV ELISA-negative, although viremic. In both patients, the onset of positivity by RT-PCR was associated with a rise of ALT levels into the ‘abnormal range’ in our laboratory. In these 2 patients, de novo acquisition of HCV infection was observed in the absence of obvious parenteral risk factors other than their presence in the HD environment. In conclusion, de novo acquisition of HCV infection may be undetected by ELISA and branched-DNA assays. The need to monitor chronic HD patients by serial ALT testing is emphasized. RT-PCR shoud be incorporated into diagnostic testing for HCV infection in chronic HD patients. RT-PCR technology can identify HCV in HD individuals with raised ALT activity.

Quantitative Assessment of HCV Load in Chronic Hemodialysis Patients: A Cross-Sectional Survey

Recent evidence has been accumulated showing that chronic hemodialysis (HD) patients have a very high prevalence of antibodies to hepatitis C virus (HCV). In contrast, there is little information addressing the virological characteristics of HCV infection in this population. Aim: To measure HCV viral load and to correlate this with demographic, biochemical, and clinical features of a large cohort of HCV-infected patients on chronic HD. Methods: 394 chronic HD patients were tested by branched-DNA signal amplification assay, anti-HCV enzyme-linked immunosorbent assay 2.0, and on the basis of the aspartate aminotransferase/alanine aminotransferase (AST/ALT) activity. Multivariate analysis by ordinal logistic regression model was performed: age, gender, race, time on HD, allocation of the patients among the HD units, etiology of end-stage renal disease, HBsAg status, anti-HCV positivity, HCV genotype, and AST/ALT levels were independent factors, and viremic levels of HCV in serum were assumed as dependent variables. Results: 88 (22.3%) patients showed serological and/or virological signs of HCV infection. 59 (15%) out of 394 had detectable HCV RNA in serum, the mean HCV load was 19.4 × 10⁵ (95% CI, 6.06 × 10⁷ to 6.2 × 10⁴) Eq/ml. According to the criteria suggested by others [J Infect Dis 1994;169:1219–1225], there were 8 (13.5%) individuals with high-titer viremia (>1 × 10⁷ Eq/ml) in the subset of viremic patients. A small subset (8/394 or 2%) of individuals was seronegative, but viremic; 29 (7%) out of 394 were seropositive without detectable HCV RNA in serum. Univariate analysis showed that the frequency of anti-HCV positivity was significantly higher in viremic patients as compared with individuals with no detectable HCV viremia: 51/59 (86%) vs. 29/335 (8.6%), p = 0.0001. Serum AST and ALT levels were significantly higher in viremic patients than in individuals with no detectable HCV RNA in serum: 23.8 (95% CI 60.8–9.3) vs. 17.1 (95% CI 50.4–5.8) U/l (p = 0.009) and 14.4 (95% CI 48.9–4.3) vs. 9.8 (95% CI, 37.3– 2.5) U/l (p = 0.008). Logistic regression analysis showed an association between HCV viremia and anti-HCV positivity (p = 0.00001) and ALT activity (p = 0.01). Conclusions: Hepatitis C virus infection is highly prevalent in the HD population; the viral load is relatively low, and it was associated with elevated hepatic enzyme levels and anti-HCV positivity. No other clinical characteristics were associated with HCV RNA levels. Seronegative but viremic patients were also found. Longitudinal studies with long follow-up periods are necessary to evaluate the course of HCV load over time in this population.

Performance of three generations of anti-hepatitis C virus enzyme-linked immunosorbent assays in donors and patients.

Prevention of posttransfusion non-A,non-B hepatitis in recipients of blood components improved considerably with the introduction of the second-generation of hepatitis C virus (HCV) antibody tests. In 1993, third-generation HCV antibody assays were introduced in Europe. The performance of three generations of anti-HCV enzyme-linked immunosorbent assay (ELISA) (ELISA-1, -2, -3) was compared in routine blood donor screening (99,394 donations were tested with ELISA-1, 167,999 donations with ELISA-2, and 262,090 donations with ELISA-3) and in serial samples from nine patients with documented acute posttransfusion HCV infection. Eight (0.01%) repeat donors, previously negative in ELISA-1, were found positive in ELISA-2 and were confirmed as positive in second-generation recombinant immunoblot assay and/or cDNA polymerase chain reaction. In the donor population, no difference in the sensitivity of ELISA-2 and -3 was observed. The specificity of the three generations of ELISAs was comparable (99.8, 99.7, and 99.7%). In seroconversion samples, ELISA-2 and -3 detected HCV antibodies at the same time in seven patients, but in two patients, ELISA-3 found HCV antibodies, respectively, 63 and 77 days earlier than ELISA-2 did. In the seroconversion samples, ELISA-2 and -3 were significantly more sensitive than second- and third-generation recombinant immunoblot assays. ELISA-3 did not detect more HCV-infected individuals in a donor population that previously tested negative in ELISA-2, but it did detect HCV antibodies earlier in some patients with acute HCV infection. ELISA-2 and -3 were significantly more sensitive than second- and third-generation recombinant immunoblot assays.

Improved reactivity of hepatitis C virus core protein epitopes in a conformational antigen-presenting system.

Recent studies have identified several epitopes in the N-terminal portion of the nucleocapsid protein which are predominantly recognized by sera of patients infected with hepatitis C virus (HCV). The characterization of the sequences recognized by theses antibodies and the evaluation of their reactivities have been performed mainly with synthetic peptides. However, synthetic peptides are notoriously unreliable as antigens when the immune response is directed against conformational epitopes. In order to improve the detection of antibody responses in HCV-infected patients, we have evaluated the reactivities of three immunodominant regions of the HCV core protein (residues 1 to 20, 21 to 40, and 32 to 46) displayed in a conformation-specific manner on the surface of the Flock House virus (FHV) capsid protein. The results obtained with these proteins in the analysis of 94 serum samples positive by anti-HCV enzyme-linked immunosorbent assay where then compared with those obtained with the corresponding synthetic peptides. The sequence most reactive both with the peptide and with the FHV protein was the region from residues 1 to 20, confirming the low conformational requirements for the display of these residues. On the other hand, the already reported conformational nature of residues 32 to 46 is in keeping with its observed high reactivity when displayed by the FHV recombinant protein and with the low reactivity displayed by its corresponding synthetic peptide. Finally, the high reactivity observed for the chimeric protein displaying the region from residues 21 to 40, as opposed to the results obtained with the synthetic peptide, also suggests that this sequence contains one or more conformational epitopes whose structures cannot be mimicked correctly with synthetic peptides.

Chronic Non-A, Non-B, Non-C Hepatitis: Is Hepatitis G/GBV-C Involved?

Background: Hepatitis G virus/GBV-C is a recently discovered virus, and its relevance in chronic hepatitis is still debated. Methods: We have previously described 127 long-term-studied and well-characterized patients with chronic non-A, non-B hepatitis (NANBH). Ninety-one (71.7%) were positive for hepatitis C virus antibodies (anti-HCV) in a first-generation anti-HCV enzyme-linked immunosorbent assay (ELISA). We now reanalyzed the same group of patients and added a third-generation anti-HCV ELISA and recombinant immunoblot assay and, in negative patients, also polymerase chain reactions for hepatitis C virus RNA, hepatitis GBV-C RNA, and hepatitis B virus DNA. Additional tests for autoimmune hepatitis types 2 and 3 were also included. Results: Anti-HCV were detected in 114 of the 123 evaluable patients (92.7%). Of the remaining nine anti-HCV-negative patients one had misdiagnosed primary biliary cirrhosis, and two had autoimmune hepatitis type 3. None of the anti-HCV-negative patients were hepatitis GBV-C RNA-, HCV RNA-, or HBV DNA-positive. Thus, 114 of 120 NANBH patients (95.0%) had chronic hepatitis C. None of the remaining six patients had received blood transfusions or was a drug addict, and two of them were successfully treated with steroids. Conclusions: Hepatitis G/GBV-C as a single cause of chronic non-A, non-B hepatitis is uncommon, and in all patients with parenteral risk factors hepatitis C was detected.

Increased detection of antibody to hepatitis C virus in renal transplant patients by third-generation assays

To assess the sensitivity and specificity of third-generation assays for antibody to hepatitis C virus (anti-HCV), sera from 244 renal transplant patients (113 positive for anti-HCV enzyme-linked immunosorbent assay [ELISA]2) were studied. Hepatitis C virus RNA was detected by a reverse-transcripted nested polymerase chain reaction. Antibody to HCV was detected by ELISA-3 in 108 (96%) ELISA-2-positive samples. Five (4%) ELISA-2-positive sera were negative by both ELISA-3 and polymerase chain reaction. In the anti-HCV-negative group, six (5%) additional cases were ELISA-3-positive; three of these were confirmed by recombinant immunoblot assay-3 (RIBA-3) and polymerase chain reaction. Recombinant immunoblot assay-3 was used to resolve 82 RIBA-2-indeterminate and three RIBA-2-negative sera. Using RIBA-3, 49 (60%) RIBA-2-indeterminate samples were positive, five (6%) ELISA-3-negative samples were negative, and 28 (34%) were remained indeterminate. Recombinant immunoblot assay-2-negative samples were indeterminate with RIBA-3. Hepatitis C virus RNA was detected in all RIBA-3-positive and 58% of the RIBA-3-indeterminate samples. Third-generation assays for anti-HCV are more sensitive and specific than second-generation assays in renal transplant patients.

Disease Markers in Blood Donors at King Fahad Hospital, AL BAHA

A total of 4683 donated blood units were screened for HCV-Ab, HBs-Ag, VDRL, malaria parasites and ALT between January 1993 and April 1994. Of the blood units, 7.7% were positive for one or two hepatitis markers (HCV-Ab, HBs-Ag), while 4.6% were positive for HCV antibody, and 3.3% of the 4.6% were accounted for by Egyptian blood donors. Thus, 73% of all positive blood units for HCV-Ab were from Egyptian donors, while the rate of positive blood units for Saudi blood donors was 0.9%. Three and one-tenth percent of the total blood units were positive for HBs antigen, 2.3% from the Saudi population. Thus, 75% of all positive blood units were from Saudi donors. The percentage for HBs-Ag blood units for Egyptians was 0.3%. The exact prevalence of HCV-Ab-positive blood units among Saudis was 1.2% and HBs-Ag-positive units was 3.3%. Prevalence of HCV-Ab-reactive blood units among Egyptians was 34% and HBs-Ag-positive units was 3.3%. HCV-RNA using PCR was detected in a total of 86% of the individuals reactive to HCV antibody. Forty-three percent of hepatitis-B- and/or C-reactive blood donors had elevated alanine aminotransferase (ALT). Elevated ALT was observed in a higher percentage among HCV-Ab-reactive blood donors as compared to HBs-Ag-reactive donors.

Hepatitis C virus antibody and hepatitis C virus replication in chronic hepatitis B patients

We assessed hepatitis C virus infection in 156 chronic hepatitis B patients using second-generation hepatitis C virus antibody (anti-HCV). Active virus replication was further investigated in anti-HCV-positive cases by means of polymerase chain reaction assay for the detection of serum hepatitis C virus RNA. Anti-HCV prevalence was higher in patients negative for hepatitis B e antigen (HBeAg) (10/48, 21%) than in HBeAg-positive patients (10/108, 9%) (p < 0.05), and the reactivity (cut-off index) in anti-HCV enzyme-linked immunosorbent assay of the positive cases was significantly higher in HBeAg-negative patients (4.1 +/- 0.1) than in -positive ones (3.6 +/- 0.6) (p < 0.05). The prevalence of hepatitis C virus RNA in anti-HCV-positive cases was also higher in the HBeAg-negative group (9/10, 90%) than in the -positive group (3/10, 30%) (p < 0.01). Viremia was found in association with high reactivity in anti-HCV ELISA (cut-off index > 3.5) in both groups. Nine (90%) of 10 such cases were viremic in the HBeAg-negative group compared with three (43%) of seven in the HBeAg-positive group (p < 0.05). These results suggest that hepatitis C virus replication may be influenced by hepatitis B virus replicative states, indicating possible interference between hepatitis B and C viruses.

Also with a restrictive transfusion policy, screening with second-generation anti-hepatitis C virus enzyme-linked immunosorbent assay would have reduced post-transfusion hepatitis C after open-heart surgery.

The incidence of post-transfusion hepatitis non-A, non-B (PTH-NANB) was prospectively assessed among open-heart surgery patients from the southeast region of Sweden before the introduction of antihepatitis C virus (HCV) blood donor screening. Blood samples for alanine aminotransferase analysis were drawn before and 2, 3, and 4 months after transfusion. Surgery was performed in four centres. Of 190 transfused and followed-up patients 2 (1.1%) contracted PTH-NANB, both operated on at the centre with significantly fewer transfusions than the other centres. One patient had antibodies to HCV detected by first-generation (C100-3) and later by second-generation anti-HCV enzyme-linked immunosorbent assay (ELISA-2) and by positive second-generation recombinant immunoblot assay (4-RIBA). The other patient, although negative by first-generation anti-HCV ELISA, was positive by second-generation ELISA and by 4-RIBA. Both patients were hepatitis C-viremic by polymerase chain reaction (PCR). All the six donors implicated in the two hepatitis cases were first-generation anti-HCV-negative, but two, one for each patient, were positive by second-generation anti-HCV ELISA. This finding was confirmed by positive 4-RIBA in only 1 donor, the other being 'indeterminate'. However, in both donors hepatitis C viremia was found by PCR. This study shows that the second-generation anti-HCV ELISA will further reduce the risk for PTH-NANB/C and draws attention to the problem of evaluation of confirmatory tests.

Performance of an Enzyme-Linked Immunosorbent Assay System for Antibodies to Hepatitis C Virus with Two New Antigens (c11/c7)

We developed an enzyme-linked immunosorbent assay (ELISA) system for antibodies to the hepatitis C virus (HCV), using two new recombinant antigens (c11 and c7) derived from the HCV genome. The performance of this ELISA system (Imucheck HCV Ab) was examined. The CV values for both intra-assay precision and reproducibility of identifying HCV antibody in the panel sera ranged from 3.5% to 6.4%. The blood elements in serum and anticoagulants did not interfere in this ELISA system. The specificity of Imucheck HCV Ab to samples from patients with non-A, non-B (NANB)-type chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma was 93.7%, 93.5%, and 81.4%, respectively. These results are more sensitive than those obtained by the first-generation anti-HCV ELISA system. In the samples from patients with NANB-type acute hepatitis, Imucheck HCV Ab enabled detection of HCV antibodies at an early stage. This system increased the sensitivity for blood donor screening and for monitoring patients with acute hepatitis.